The present invention relates to a vehicle occupant protection system, and in particular to a vehicle occupant protection system for protecting the vehicle occupant from the impact of a side crash.
In recent years, to the end of improving the protection of the occupant of a motor vehicle from the impact of a side crash, various vehicle body structures have been proposed which minimize the deceleration of the passenger compartment and prevent the deformation of the vehicle body from reaching the passenger compartment by appropriately controlling the deformation mode of the part (crushable zone) of the vehicle body other than the passenger compartment (see Japanese patent laid open publication No.7-101354).
According to such a conventional vehicle body structure, the crushable zone for absorbing the impact of a frontal crash can be provided by the length of the engine room, but the crushable zone for the impact of a side crash cannot be adequately provided by the thickness of the door. Therefore, it has been practiced to provide a reinforcing bar inside the door to prevent the deformation of the door from affecting the passenger compartment as a measure against a side crash.
However, because such a conventional measure against a side crash is based on the prevention of the deformation of the door so as to prevent the door from intruding into the passenger compartment, it inevitably detracts from the absorption of the impact acting upon the vehicle body, and is unable to adequately prevent the vehicle occupant from moving toward the door under the acceleration acting on the vehicle body.
In view of such problems of the prior art, a primary object of the present invention is to provide a vehicle occupant protection system which can favorably control the impact to the vehicle occupant at the time of a side crash.
A second object of the present invention is to provide a vehicle occupant protection system which prevents the vehicle occupant from colliding with the door at the time of a vehicle side crash.
A third object of the present invention is to provide a vehicle occupant protection system which can be fitted within a limited available space around the seat of the vehicle occupant.
According to the present invention, such objects can be accomplished by providing a vehicle occupant protection system, comprising a seat fitted with a seat belt for restraining a vehicle occupant and laterally moveably supported by a floor, said seat belt having two ends attached to the seat; a crash load input member having a higher rigidity than the vehicle body, the crash load input member being connected to the seat and having one end extending to a part adjacent to a side sill; and brake means for applying an opposite force to the seat after it has traveled a certain distance toward the central part of the vehicle body.
Thus, the crash load input member having a higher rigidity than the vehicle body causes the acceleration acting on the seat to rise before the acceleration acting on the vehicle body does during an early phase of a vehicle crash. Thereafter, the velocity (deceleration) of the seat is equalized to that of the vehicle body during an intermediate phase of the vehicle crash by the brake means. This favorably controls the maximum level of acceleration acting upon the vehicle occupant. The maximum level of acceleration determines the degree of the injury which the vehicle occupant sustains at the time of a vehicle side crash. Furthermore, the seat moves toward the central part of the vehicle body or away from the door panel before the side panel of the vehicle body is pushed into the passenger compartment so that an enlarged space is created between the vehicle occupant and vehicle body. This prevents the injury to the vehicle occupant that could be caused by the collision with the vehicle door panel intruding into the passenger compartment.
The crash load input member may have an inboard end attached to the seat and an outboard end located at a side part of the vehicle body, such as a part adjacent to the side sill, where an impact from a side crash is substantially directly transmitted. For a favorably controlled action of the crash load input member, it may be slidably supported by the upper or lower surface of the floor by using an appropriate slide bearing.
The seat is preferably provided with a restraining member for restraining the vehicle occupant from moving outwardly with respect to the seat so that the vehicle occupant may be held firmly to the seat and experience the designed time history of acceleration according to the present invention. The restraining member may consist of an armpit belt passed around an upper part of the vehicle occupant and/or an extension of a seat back extending forward from an outboard side thereof.
The brake means may consist of a power actuator, but more preferably consists of a member adapted to undergo a controlled deformation by a part of the seat as it travels toward the central part of the vehicle body. Such a member provides the required braking action in a more economical and simple manner.
To achieve the necessary motion of the vehicle seat at the time of a side crash without interfering with the existing arrangement for the fore-and-aft adjustment of the vehicle seat, the seat may be supported by the floor via a laterally extending rail which is in turn guided by a longitudinally extending rail attached to the floor for a fore-and-aft adjustment of the seat. In such a case, the power actuator may be attached to the floor if its working end is connected to the seat via a coupling for accommodating the fore-and-aft adjustment of the seat.